as always depends on budget but i'm wondering if a steep gable roof at right angles to the main roof with a raked ceiling and solar roof vents would allow better ventilation with enough headroom for a ceiling fan and adding some panels of transluscent insulated polycarbonate closer to the house would help avoid the overshading ...we've used a diy double layered polycarbonate and there are insulating products available eg Arcpanel and, to improve light inside the house (or under a dark alfresco roof) consider Solar Skylights (not hole in the roof) like Arcol or illume brand that we use with excellent results for a modest investment, DIY installation and no risk of roof leaks

A custom design and build will generally be more expensive than a project home of a similar speciifcation. If you are happy to make a few compromises the cheapest approach would be to find a project builder with a standard plan that matches your requirements as close as possible. Remember that most project builders can flip an entire plan from left hand to right hand, but most will not want to make significant alterations and redesign of their standard plans. It all comes down to your budget and what compromises you are prepared to make (or not make). Also you should be aware about the copyright that exists in all project and custom design house plans. It is illegal to take a plan from one builder, make a few changes, and ask another builder to construct it. https://undercoverarchitect.com/can-you-use-a-floorplan-you-find-online/ When you engage a professional to design your home from scratch (without reference to builder's copyrighted plans) you can get exactly what you want, and arrange competitive quotes between builders. Best of luck, Dr Retro of Dr Retro House Calls

Could you put on the plans the orientation and maybe name some more of the rooms? Currently renting a somewhat similar layout and could make some suggestions once I know the orientation and what the other rooms are.

put the carport higher up the block with a longer driveway?..anything is possible if you move enough earth but could you have the garage and main living areas closer together and the deck to one side as a half way point .ie with less steps between each level and spread further along the block and not one on top of the other..what's the width and length of the block and the distance from the front boundary to the beginning of the steep section and then the length of the steep section..if you haven't already done so a detailed contour survey will help suggest the best options